package QL;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.SignatureException;

/**
 * MD5加密类
 * @author tgh
 *
 */
public class MD5 {
	
	/**
	 * MD5 16位加密
	 * @param plainText
	 * @return
	 */
	public final static String digest(String plainText) {
		String md5Str = null;
		try {
			StringBuffer buf = new StringBuffer();
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update(plainText.getBytes());
			byte b[] = md.digest();
			int i;
			for (int offset = 0; offset < b.length; offset++) {
				i = b[offset];
				if (i < 0) {
					i += 256;
				}
				if (i < 16) {
					buf.append("0");
				}
				buf.append(Integer.toHexString(i));
			}
			md5Str = buf.toString().substring(8, 24);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return md5Str.toUpperCase();
	}
//	
//	public static void main(String[] args) {
//		System.out.println(digestfull("zhangxueyou111111").toUpperCase());
//		System.out.println(byteArrayToHexString("9edf4692d8eeb763".getBytes()));
//	}

	/**
	 * MD5 32位加密
	 * @param plainText
	 * @return
	 */
	public final static String digestfull(String plainText) {
		String md5Str = null;
		try {
			StringBuffer buf = new StringBuffer();
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update(plainText.getBytes("utf-8"));
			byte b[] = md.digest();
			int i;
			for (int offset = 0; offset < b.length; offset++) {
				i = b[offset];
				if (i < 0) {
					i += 256;
				}
				if (i < 16) {
					buf.append("0");
				}
				buf.append(Integer.toHexString(i));
			}
			md5Str = buf.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return md5Str.toUpperCase();
	}
	

    /**
     * @param content
     * @param charset
     * @return
     * @throws SignatureException
     * @throws UnsupportedEncodingException 
     */
    @SuppressWarnings("unused")
	private static byte[] getContentBytes(String content, String charset) {
        if (charset == null || "".equals(charset)) {
            return content.getBytes();
        }
        try {
            return content.getBytes(charset);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("MD5签名过程中出现错误,指定的编码集不对,您目前指定的编码集是:" + charset);
        }
    }
    
    private static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++)
			resultSb.append(byteToHexString(b[i]));

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n += 256;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String MD5Encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname))
				resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
			else
				resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
		} catch (Exception exception) {
		}
		return resultString;
	}

	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "A", "B", "C", "D", "E", "F" };
}

